ABB REB670 Applications Manual page 213

1MRK 505 337-UUS -
Application manual
FunctionMode: This parameter can be set to Current or Contact. This states the way the
detection of failure of the breaker is performed. In the mode Current the current
measurement is used for the detection. In the mode Contact the long duration of initiate
signal (trip) is used as indicator of failure of the breaker. The mode Current&Contact
means that both ways of detections are activated. Contact mode can be usable in
applications where the fault current through the circuit breaker is small. This can be the
case for some generator protection application (for example, reverse power protection) or
in case of line ends with weak end infeed.
RetripMode: This setting states how the re-trip function shall operate. Retrip Off means
that the re-trip function is not activated. CB Pos Check (circuit breaker position check) and
Current means that a phase current must be larger than the operate level to allow re-trip.
CB Pos Check (circuit breaker position check) and Contact means retrip is done when
circuit breaker is closed (breaker position is used). No CB Pos Check means re-trip is done
without check of breaker position.
Pickup_PH: Current level for detection of breaker failure, set in % of IBase. This
parameter must be set so that faults with small fault current can be detected. The setting
can be chosen in accordance with the most sensitive protection function to initiate the
breaker failure protection. Typical setting is 10% of IBase.
PU_BlkCont: If any contact based detection of breaker failure is used this function can be
blocked if the current is larger than this setting level. If the FunctionMode is set to
Current&Contact breaker failure for high current faults are safely detected by the current
measurement function. To increase security the contact based function must be disabled
for high currents. The setting can be given within the range 5 – 200% of IBase.
t1: Time delay of the re-trip. The setting can be given within the range 0 – 60 s in steps of
0.001 s. Typical setting is 0 – 50 ms.
t2: Time delay of the back-up trip. The choice of this setting is made as short as possible
at the same time as unwanted operation must be avoided. Typical setting is 90 – 150 ms
(also dependent of re-trip timer).
The minimum time delay for the re-trip can be estimated as:
³ + +
t 2 t 1 t t
cbopen BFP reset _
EQUATION1430 V1 EN
where:
t is the maximum opening time for the circuit breaker
cbopen
t is the maximum time for breaker failure protection to detect correct breaker function (the
BFP_reset
current criteria reset)
t is a safety margin
margin
+
t
margin
Section 7
Current protection
(Equation 43)
207